It has been a goal in the building and waste disposal industries to make concrete or cement bodies relatively impermeable to water. The building industry is concerned because water which penetrates concrete can, as a result of alternate freezing and thawing, cause surface layers of the concrete to spall, or, in extreme cases, cause the concrete body to break into smaller pieces.
One method of disposing of wastes, especially radioactive aqueous wastes, contemplates using an aqueous waste solution to provide the water of hydration in forming a concrete or grout mass. However, unless precautions are taken, the resulting body may be sufficiently permeable to water so that radioactive components can be leached from the solidified mass.
Attempts have been made in the prior art to impregnate concrete with polymers to form a relatively impermeable mass. However, the permeation of organic-based polymers even a few inches into such a material has met with only limited success due to the low permeability of the concrete mass and the presence therein of water and air which impedes the movement of low density, hydrophobic liquids. In some instances, nearly complete drying of the concrete mass is necessary to remove the water in order to obtain even limited penetration. In some cases, vacuum has been used to remove entrained air from a solid, and in others high pressure has been used to force a polymer into a solid. Attempts at mixing a polymer with grout prior to solidification has, in some instances, interferred with the hydration of the cement which is necessary to form the solid, or has resulted in the separation of phases because of density differences. The usefulness of these processes is, in general, limited to small-scale, relatively thin material that could be expected to be completely impregnated by these techniques.